what compression ratio?

[Xracer729]

ok every bodies sayin that we need to lower the CP of the 2zz to run say 10psi safely, so...what is a good CP to run a good amount of boost 10-20psi

[Oo DaRk StAr oO]

8.5:1... but I dont think the engine will handle over 15 safely.

[CheezeFrog]

Originally posted by Oo DaRk StAr oO
8.5:1... but I dont think the engine will handle over 15 safely. Why? Can't you just back off on the timing and/or add more fuel to prevent detonation? Would seem more elegant than tearing the engine apart and throwing in some low compression slugs in there.

[Oo DaRk StAr oO]

I dont think that would be a good Idea. I'm putting 9:1 or 8.75:1 in my GT.

[CheezeFrog]

I just bought some Arias 11.5:1 pistons and plan on running 10-12psi on 93 octane pump gas on a B18C1. In a few weeks we'll see if I'm right or wrong in my decision.

[Oo DaRk StAr oO]

Your Hatchbeezy will go boom! Thats too much Compression.

[Oo DaRk StAr oO]

Look @ the WRX's and Supras 8.5:1 Compression Ratios.

[Xracer729]

Originally posted by CheezeFrog
I just bought some Arias 11.5:1 pistons and plan on running 10-12psi on 93 octane pump gas on a B18C1. In a few weeks we'll see if I'm right or wrong in my decision.
your freakin crazy the 2zz has trouble running 8psi and your gonna run more then 10 im with dark star on this one engine go BOOM!!!:bang:

[Oo DaRk StAr oO]

Hey cheeze i liked ur sig whered it go?

[CheezeFrog]

heheh, well we'll see how it works out. 11.5:1 does sound high for a forced induction motor, let alone one expected to run on pump gas. But I have confidence in my builder/tuner. His old Civic ran 10.9:1 CR on pump gas, daily driven. In fact, it went as quick as 10.5 in the 1/4 on race gas. I'll let you guys know what we did if it works. If it doesn't, I'll tell you what went wrong.

Here ya go, Darkstar :)
http://www.houston-imports.com/~cheezefrog/hatchbeezy.jpg

[Oo DaRk StAr oO]

Hell Yeah!!!! I love that sig!!!

[Xracer729]

hey dark star get any vids of that exhaust yet?

[Oo DaRk StAr oO]

my cars getting turbod about an hour away from me. Will do it when i get my car back.

[larryd]

high compression + boost doesnt automatically equal BOOM.. high compression + boost without tuning = boom.. lesson learned here?? TUNING is key..

[Oo DaRk StAr oO]

id be interested to see that pull some high boost.

[monkeywrench]

For 95% of our customers we recommend 8.8:1 compression. It's not just a number we picked out of thin air; that compression ratio allows the engine to run safely with some pretty impressive boost levels, while not killing off-boost power.

True, higher compression can be made to work with good tuning, but the stock 11.5:1 is definitely too high for a durable street turbo setup.

[Xracer729]

what material should these pistions be made out of?

[monkeywrench]

The piston makers all have their own special blend. Most of the more durable pistons (JE, Arias, etc) that like boost expand a lot with heat, so you get piston slap when cold. We deal mostly with Wiseco, which uses an alloy that is much better suited to a street car, while retianing excellent strength. They're made from 2618 aluminum.

[Oo DaRk StAr oO]

How about u guys sponsor me and ill test them out heheheee....

[celicauk]

Nice try Matt :)

Mine runs 8.86:1 with a max of 12psi boost from the SC.

[Oo DaRk StAr oO]

thats where im shootin Simon... 8.8-9:1

[Xracer729]

what was the compression ratio on that EIP turbo 2zz or what ever it was?